Circuit breaker with interlocked blast valve and contact motors



May 20, 1952 c. D. AINSWORTH 2,597,047

CIRCUIT BREAKER WITH INTERLOCKED BLAST VALVE AND CONTACT MOTORS Filed Oct. 5, 1949 I03 //5 Q5 9 7 o 33 /0/ //2 45 8 K24 ay 0 (9mm $9. mm

QMM f 5 mod/W Patented May 20, 1952 CIRCUIT BREAKER WITH IN TERLOCKED BLAST VALVE AND CONTACT MOTORS Chester D. Ainsworth, Wollaston, Mass, assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Applicationflctohcr 3, 1949, Serial No. 119,284

6 Claims.

This invention relates to electric circuit breakers, and more particularly to operating mechanisms for electric circuit breakers of the fluid operated type.

In a fluid operated electric circuit breaker a source of fluid under pressure is usually connected to a fluid motor through a control valve for controlling the operation of the circuit breaker. Such control valves heretofore have been used for causing opening of the switch or circuit breaker arcing contacts. It is essential, however, that the control arrangement embodying such a circuit breaker opening valve be designed to cause opening of the valve at the proper time and in proper sequence with other circuit breaker control equipment. Many complicated arrangements have been used heretofore to control such a fluid motor but most of these arrangements were unduly involved and designed for the particular circuit breaker system used therewith.

In accordance with the invention claimed a new and improved operating mechanism comprising two fluid operated motors, properly interlocked so as to obtain rapid sequence of operation is provided. The first fluid operated motor actuates a blast valve which provides an are extinguishing blast of gas through an arcing chamher which houses the arcing contacts. The first motor substantially simultaneously actuates a mechanical interconnecting means which causes opening of a control valve which actuates a sec- 0nd fluid operated motor. The second motor separates the arcing contacts of the circuit breaker to draw an are which is rapidly and e ficiently extinguished by the blast of gas. This improved arrangement provides a system which is effective for separating the arcing contacts only upon operation of the blast valve associated therewith.

It is, therefore, one object of the present invention to provide a new and improved pneumatic operating mechanism for circuit breakers of the fluid blast type.

Another object of the present invention is to provide a new and improved arrangement for a contact actuating fluid motor.

A further object of this invention is to provide a new and improved arrangement for two fluid motors in which one motor is so interlocked with the other motor as to provide a rapid sequence of operation.

A still further object of this invention is to provide a new and improved arrangement for a fluid operated electric circuit breaker in which the contact separating fluid motor is controlled by a blast valve actuating mechanism.

A still further object of this invention is to 2 provide a new and improved arrangement for a fluid operated electric circuit breaker in which contact separation is prohibited if an associated blast valve fails to open.

Objects and advantages other than those set forth will be apparent from the following description when read in connection with the accompanying drawing in which the single figure is a diagrammatic showing of a circuit breaker and a pneumatic operating mechanism therefor emhodying the present invention.

Referring more particularly to the drawing by characters of reference, the figure illustrates a circuit breaker including as a constructive element thereof a reservoir 6 constituting a source of supply of fluid under pressure, which will be assumed herein to be compressed air, supplied from a suitable compressor (not shown). Although in general, circuit breakers of the type herein considered are provided with a plurality of similar pole structures, one for each phase of a polyphase electric circuit, only one such pole structure or pole unit is shown in the figure and the circuit breaker will be described in detail as if it were of the single pole type.

The circuit breaker comprises a fixed arcing contact 1 and a cooperating movable arcing contact 8 connected in an electric circuit through terminal studs 9 and I 6. The arcing contacts are mounted to engage within an arcing chamber H which is aligned with an arc chute [2. The arcing chamber II is axially aligned with a hollow insulator [3 which provides a connection between reservoir 6 and arcing chamber 1 I through a suitable blast valve M for the purpose of directing a blast of arc eXtinguishing fluid under pressure between the arcing contacts and through the arcing chamber I l.

The differential type blast valve l4 comprises fluid motors l5 and I! for controlling a blast inlet port [8. Motor 16 comprises a cylinder 29, a piston 2|, a piston rod 22, a spring 23, and an inlet port 24. Motor I'l comprises a cylinder 25, a piston 26, a return spring 21 for piston 26, a vent 28 and an exhaust port '29. Valve '3l for closing an exhaust port 32 is adapted to be operated by motor l1. Cylinder 3'3 cooperates with cylinder 25 of motor I! to provide an exhaust port 34. Piston 26, when actuated by air under pressure actuates valve 3| and opens exhaust port 32 against the action of spring 21. As long as exhaust port 32 remains closed, air under pressure supplied from reservoir 6 through inlet port 24 cooperates with spring 23 to maintain piston 2| in the position shown.

Inlet port 35 of blast valve l 4 supplies fluid motor I! with operating fluid under pressure for actuating piston 26. Inlet port 35, however, is controlled by a slide valve I5 provided with a piston I9 which opens and closes port 35 upon predetermined circuit conditions.

A solenoid type control or trip valve 36 controls the opening of blast valve I4 upon the occurrence of a predetermined electrical condition of the electric circuit controlled. Control valve 38 may be of any suitable known type and is diagrammatically shown as a valve of the ma netic type. Pipes 44 and 45 connect valve 36 to difierential type blast valves associated with other phase structures of the circuit breaker. Pipe 46 connects valve 36 to reservoir 6.

The movable arcing contact 8 is actuated by a fluid motor 41 through the medium of a crankshaft 48, a pair of cranks 5|, 52, and a connecting rod 53. Fluid motor 41 comprises a cylinder 54, a piston 55, a hollow piston rod 56 movable with piston 55 and connected through a link 51 to crank 5I, ports 59, 60, a pair of control valves 58, 6| for ports 62, 63, respectively, springs 64, 65 for biasing control valves 58, 6!, respectively. to their closed positions, valves 66, 61, and springs 68, H for biasing valves 66, 61, respectively, to their closed positions. Piston rod 56 is provided with a plurality of exhaust ports 12, 13 for exhausting pressure from the ends of the cylinder. A pipe line 69 connects port 10 of motor 41 to slide valve I5.

The contact actuatin fluid motor 41 is controlled by a valve 15 which regulates the time at which fluid under pressure is supplied from reservoir 6 through a pipe line 16 to motor 41. Valve 15 comprises a valve element 82 forming a valve stem 83, a biasing spring 84 and ports 85, 86, 89 and 90. Spring 84 biases valve element 82 in valve closing direction, thus closing port 85 and prohibiting the passage of air from pipe line 16 through port 89, valve 15 and port 90 to air inlet port 60 of motor 41. As illustrated in the drawing, valve 15 may be mounted immediately adjacent motor 41 with port 90 of valve 15 and port 60 of motor 41 interconnected.

Valve 15 is connected by means of port 86 and pipe line 81 to an inlet port 88 of trip predominating valve 11. Trip predominating valve 11 further comprises a cylinder 9|, piston 92, valve element 93, a spring 94, and an inlet port 96 which is connected to a suitable solenoid type closing control valve 91 and a port 99 interconnected with a port 18 of cylinder 54. Control valve 91 is connected to reservoir 6 through pipe line 98.

In accordance with the invention claimed a means such as a mechanical interconnecting rod and lever arrangement is provided for actuating control valve 15 upon actuation of piston 2I and piston rod 22 of motor I6. This interconnecting rod and lever arrangement comprises a lever I pivoted at a point I02 with one end thereof connected at a point I03 to piston rod 22 and the other end connected to one end of a connecting rod I04. The other end of connecting rod I04 is pivotally secured to a crank I which oscillates with a shaft I06 through a given arcuate path. A second crank I01 mounted on shaft I06 and provided to oscillate through a given arcuate path therewith, actuates valve stem 83 of control valve 15 upon clockwise movement thereof. Fuid motor I6 controls fluid motor 41 through the medium of control valve 15 and thus provides for rapid sequential operation thereof.

A pneumatic brake I08 comprising brake shoes III acting on a drum II2 connected to shaft 48 is provided for arresting the movement of shaft 48 at a predetermined time to lessen the impact of the moving mass of the movable contact assembly. Piston 55 controls the supply of air from cylinder 54 of motor 41 through a pipe II4 to a cylinder II6 provided with a piston H5. The cylinder and the piston are connected to brake shoes III to produce the retarding action.

The circuit breaker illustrated in the drawing is shown with the cooperating arcing contacts in the closed circuit position and the pneumatic operating mechanism in the corresponding position. An opening operation is initiated by energization of the tripping solenoid control valve 36, thereby causing air under pressure from reservoir 6 to pass through pipe 46 to and through valve 36, valve I5 through port 35 to the fluid motor I1 and to any similar motors associated with other phase structures of the circuit breaker. Air under pressure causes piston 26 of motor I1 to move against the action of spring 21 and to actuate valve 3I, thus opening port 32 which exhausts the air under pressure trapped in cylinder 20 through ports 34. This exhausting action reduces the pressure behind piston 2| 0! fluid motor I6 and enables the air under pressure in reservoir 6 acting on the portion of the top side of piston 2I surrounding the seat of the blast valve to overcome the action of spring 23. A blast of air under pressure then passes through the hollow insulator I3, through the arcing chamber II and into the arc chute I2.

Upon the actuation of piston 2 I of fluid motor I6 in blast valve opening direction, piston rod 22 of fluid motor I6 rotates lever IOI counterclockwise, which in turn actuates connecting rod I04 to rotate crank I05 and shaft I06 clockwise. Clockwise rotation of shaft I06 causes actuation of shaft 83 of control valve 15 in valve opening direction, thus causing air under pressure from reservoir 6 to flow through pipe line 16, to and through valve 15, through port and into cylinder 54 of contact actuating fluid motor 41 and into pipe 69. Air under pressure in the contact opening end of cylinder 54 passes through ports 62 and overcomes the bias of spring 64 to open control valve 58 and actuate piston 55 in contact opening direction. Upon movement of piston 55 in contact opening direction, piston rod 56 of fluid motor 41 rotates crank 5|, shaft 48, and crank 52 counterclockwise, thus actuating connecting rod 53 to separate the arcing contacts 1, 8. Movement of piston 55 in contact separating direction opens port 59, and air under pressure flows through pipe II4 to cylinder N6 of brake I08. Movement of piston II5 under the action of air under pressure applies the shoes of brake I08 to retard the movement of the moving arcing contact 8.

Ports 12, 13 are provided in the hollow piston rod 56 of motor 41 for exhausting the air under pressure that might be trapped in the cylinder 54 on the trailing side of piston 55 at the end of its stroke, thus permitting rapid reversal motor action. In addition, valves 66, 61 are so designed to overcome the biasing action of their respective springs 68, H to permit rapid exhausting of the air under pressure on the leading side of piston 55.

In order to conserve air under pressure in reservoir 6 and to rapidly close the blast valve at a predetermined time, air under pressure in pipe line 69 actuates piston I8, thus closing the air inlet port 35 to blast valve I4 and any other blast valves of the circuit breaker. The pressure on piston 26 of motor 11 is relieved by exhaust port 29, and spring 21 biases piston 26 to the position shown. Any air under pressure having leaked past piston 26 is exhausted through vent 28. The movement of piston 26 under the action of spring 21 lowers valve 3| against its valve seat and permits a back pressure to build up under piston 21 such that in combination with the biasing action of spring 23 returns piston 2| to the'position shown, thus closing blast valve M.

A closing operation is initiated by energize,- tion of the closing solenoid control valve 91, thereby causing air under pressure from reservoir 6 to pass through valve 91, port 96 of valve 11, valve 11, port 18 of cylinder 54, and into the closing end of fluid motor 41. lhe air further flows through ports 63, opens valve 61 against the biasing effect of spring 65 and actuates piston 5.5 of fluid motor 4'! in contact closing direction, thus closin the arcing contacts.

If opening and closing impulses are substantially simultaneously initiated by valves 36 and 9], respectively, air under pressure from pipe line 15 flows through control valves 15, port 86 of valve 15, pipe 8?, inlet port 83 of trip predominating valve ll and actuates piston 92 thereof upward, thus actuating valve element 93 to close port 99 in cylinder 9|. Closing air from valve 91 is, thus, restrained from reaching cylinder 54 through port 99 of trip predominating valve I? and port 18 of fluid motor 47 to close the arcing contacts. Once valve element 93 is actuated to closed position, no contact closing pressure impulse can be passed through valve ll as long as closing solenoid valve 9'! remains open. Valve 91 feeds air to the chamber below valve element 93 thereby holding valve element 93 in closed position. As long as the blast valve remains open, air is supplied under piston 92 through valve 15, which action also holds valve element 93 in closed position.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure ters Patent:

1. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing by Le tan are, a blast valve for controlling a fluid blast from said source for extinguishing the are drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor arranged to operate in sequence with said blast valve comprising a cylinder and a piston for separating said arcing contacts, valve means for controlling the time at which fluid under pressure is supplied to said second motor, and linkage means interconnecting said valve means and said piston of said first motor for actuating said valve means upon actuation of said first motor.

2. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an arc, a blast valve for controlling a fluid blast from said source for extinguishing the are drawn upon separation of said arcing contacts, a. first fluid operated motor comprising a cylinder and a piston for actuating said "blast valve, a second "fluid operated motor comprising a cylinder and a piston for separating said arcing contacts, a control valve arranged immediately adjacent said second motor and controlling the connection between said second motor and said source for causing actuation of said second motor substantially simultaneously with the actuation of said control valve, and means interconnecting said control valve and said piston of said first motor for actuating said control valve upon movement of said piston of said first motor in blast valve opening direction.

3. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an arc, a blast valve for controlling a fluid blast from said source for extinguishing the are drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor for separating said arcing contacts, a control valve comprising 3, cylinder defining a port and a valve element for controlling said port arranged immediately adjacent said second motor and controlling the connection between said second motor and said source for causing actuation of said second motor substantially simultaneously with the actuation of said control valve, and means interconnecting said control valve and said piston of said first motor for actuating said valve element upon movement of said piston in blast valve opening direction to cause fluid under pressure from said source to pass through said port to actuate said second motor.

l. In a fiuid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an are, a blast valve for controlling a fluid blast from said source for extinguishing the are drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor comprising a cylinder and a piston arranged to actuate said arcing contacts to circuit open and circuit closed positions, a first valve for controlling the time at which fluid under pressure is supplied from said source to said second motor for actuating said arcing contacts to circuit open position, a second valve for controlling the flow oi fluid from said source to said second motor for actuating said arcing contacts to circuit closed position, linkage means connected to the piston of said first motor for actuating said first valve upon a predetermined movement of said first motor, and means controlled by said first valve for rendering said second valve ineffective during movement of said first motor in contact opening direction.

5. In a fluid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an are, a blast valve for controlling a fluid blast from said source for extinguishing the are drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor comprising a cylinder and a piston arranged to actuate said arcing contacts to circuit open and circuit closed positions, a first valve for controlling the time at which fluid under pressure is supplied from said source to said second motor for actuating said arcing contacts to circuit open position, a second valve for controlling the flow of fluid irom said source to said second motor for actuating said arcing contacts to circuit closed position, linkage means connected to the piston of said first motor for actuating said first valve upon a predetermined movement of said first motor, and a third valve controlled by the fluid under pressure fiowing through said first valve for rendering said second valve ineffective during movement of said arcing contacts in circuit opening direction.

6. In a fiuid blast circuit interrupter, the combination comprising: a source of fluid under pressure, separable arcing contacts for establishing an are, a blast valve for controlling a fluid blast from said source for extinguishing the are drawn upon separation of said arcing contacts, a first fluid operated motor comprising a cylinder and a piston for actuating said blast valve, a second fluid operated motor comprising a cylinder and a piston arranged to actuate said arcing contacts to circuit open and circuit closed positions, a first valve connected to one end of the cylinder of said second motor for controlling the time at which fluid under pressure is supplied from said source to said second motor for actuating said arcing contacts to circuit open position, a second valve connected to the other end of the cylinder of said second motor for controlling the fiow of fluid from said source to said second motor for actuating said arcing contacts to circuit closed position, linkage means connected to the piston of said first motor for actuating said first valve upon a predetermined movement of said first motor, and a third valve connected to said other end of said cylinder between said cylinder and said second valve and controlled by the fiuid under pressure flowing through said first valve for rendering said second valve ineffective during actuation of said arcing contacts in circuit opening direction.

CHESTER D. AINSWORTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,817,552 Galloway Aug. 4, 1931 2,050,619 Malott, Jr Aug. 11, 1936 2,130,618 Gnavi Sept. 20, 1938 2,184,057 Parker Dec. 19, 1939 2,186,379 Harrington Jan. 9, 1940 2,301,028 Esch Nov. 5, 1942 

